2012 EDUCATIONAL BOOK - American Society of Clinical Oncology

Fig. 4. Abbreviations: ER, estrogen receptor; y, year; SE, standard error; (O-E)/V, (observed-expected)/variance.
Reprinted from The Lancet, 378, Early Breast Cancer Trialists’ Collaborative Group, Davies C, Godwin J, et al. Relevance of breast cancer
hormone receptors and other factors to the efficacy of adjuvant tamoxifen: Patient-level meta-analysis of randomised trials, 771–784, 2011,
with permission from Elsevier.
Radiation Therapy
The Overview has also enabled powerful analyses of the
effects of radiotherapy for early-stage breast cancer. The
proportional effects of radiotherapy after breast-conserving
surgery are substantial for both node-negative and nodepositive
disease as shown in Fig. 5. There are substantial
reductions in any recurrence and improvements in breast
cancer survival with postsurgical radiotherapy after breastconserving
surgery.
An important question regarding radiotherapy for breast
cancer has been whether all-cause mortality would be enhanced
by radiation treatments or whether late (rare) side
effects of radiation might negate treatment benefits in
breast cancer–specific mortality. The Overview, with its
large number of trials and patients, is uniquely positioned to
address this question. Recent data (Fig. 6) indicate that
radiotherapy after breast-conserving surgery reduces breast
cancer recurrence and all-cause mortality among both nodepositive
and node-negative disease. A one in four rule
applies for patients with pN0 and pN1 disease in that one
death is prevented for every four recurrences that are
prevented. These benefits are not substantially reduced by
side effects and are durable through 15 years of follow-up.
74
Chemotherapy
PRITCHARD, BERGH, AND BURSTEIN
The recent overview analysis was published in The Lancet
in December 2011 and was based on the analysis of 100,000
randomly selected patients treated in different randomized
studies. 5
In short, the overview contained the quinquennial update
of the following:
Nontaxane chemotherapy compared with taxanes in
44,000 patients
Different anthracycline based regimens in 6,000 patients
Anthracyclines in the comparisons compared with CMF
in 18,000 patients
Randomized studies in 32,000 patients comparing no
chemotherapy with polychemotherapy
For this EBCTCG round, the chemotherapy regimens
were, for the first time, grouped based on scheduling and
dose intensity, with particular focus on the CMF- and
anthracycline-based regimens. All outcome analyses were
done based on individual patient tumor data with as long of
follow-up as possible for each study. Individual patient data
were also included from some unpublished randomized stud-